Attention, Bernie Sanders supporters: Hillary Clinton wants you to know she does NOT support President Obama's Trans-Pacific Partnership trade deal. Not now, not ever.

"My message to every worker in Michigan and across America is this. I will stop any trade deal that kills jobs or holds down wages, including the Trans-Pacific Partnership," she said in an economic speech outside Detroit on Thursday. "I'll oppose it now, I'll oppose it after the election and I'll oppose it as president."

That's about as clear as it gets. Clinton was trying to convince progressives who have been skeptical of her stance on trade that she is, indeed, on their side. And it seemed to have worked. Mostly.

An influential group of progressives wants Clinton to do just one more thing to prove her loyalty. But that one more thing could make Clinton choose between two allegiances in the party she'll want to have on her side to win in November: them or Obama.

Democracy for America, an influential group in the progressive movement founded by former Vermont governor and 2004 presidential candidate Howard Dean, sent out a statement Thursday praising Clinton's comments on trade.

They are "the strongest we've heard from her to date and will undoubtedly help build the support necessary to kill this miserable trade deal once and for all," Charles Chamberlain, director of Democracy for America, said in a statement.

He then called on her to directly challenge Obama by demanding that he stop trying to get Congress to pass his trade deal before he leaves office:

"However, it's now more important than ever that the country and President Obama hear specifically from Secretary Clinton that a vote on the job-killing TPP during a lame-duck session of Congress must not happen."

Doing so would require making Clinton's journey across the narrow tightrope she's walking with her party on trade even more precarious.

Clinton has repeatedly said she wants to continue to improve on what Obama has done for the past eight years — so her decision in the primaries not to support the president's trade deal was an awkward divergence. It helps that Obama is incredibly popular among Democrats right now. And with others — half the nation or more.

Even after Clinton took a position on trade that more closely aligned her with the Bernie Sanders wing of the party, skepticism on the left abounded. Progressives didn't easily forget she advocated for the deal while she was secretary of state. Anti-TPP protesters were some of the most visible and vocal protesters at the Democratic convention in July.

It didn't help that during that sometimes contentious convention, one of Clinton's closest allies suggested that she's opposing the TPP deal now, but will support it if she's elected. Virginia Gov. Terry McAuliffe (D) quickly walked that back, but the damage may have been done.

A recent Suffolk University poll showed Clinton and Trump basically tied in Iowa, despite the fact the state has voted for the Democratic presidential candidate all but one time in the past 24 years. As my colleague Philip Bump pointed out, the poll found significant holdouts among Sanders supporters in Iowa — who tend to be anti-TPP.

Meanwhile, Obama is trying to make this whole Clinton-TPP thing a moot issue. He's pushing Congress to give the final approval to this deal sometime this fall. Because Congress is controlled by Republicans, and Republicans tend to be more supportive of trade, there's a chance that could happen (although perhaps after the November elections. Hence Democracy for America's focus on the "lame duck" session of Congress.)

Which brings us back to the dance between progressives and Clinton. They are essentially daring Clinton to try to stop a trade vote from happening this year. If she's really on their side, their logic goes, she'd call out Obama for the good of the country. The line they're drawing is clear: them or Obama.

Clinton took a big step Thursday toward the progressive line of her party. She gave herself very little to no wiggle room if she ever does want to support the president's trade deal. (Although she did say and has consistently said she supports trade deals that meet her "high bar.")

The question is whether she'll continue walking with the progressive wing of her party on the TPP when it requires a much more direct confrontation with Obama — a guy who just happens to be one of the most popular figures in the Democratic Party right now.